Tweco PCM-120 Machine Torch - Manual (Page 31)

Manual 0-2698 5-1 CUSTOMER/OPERATOR SERVICE
SECTION 5:
CUSTOMER/OPERATOR
SERVICE
5.01 Introduction
This section describes basic maintenance procedures per-
formable by operating personnel. No other adjustments
or repairs are to be attempted by other than properly per-
sonnel.
WARNINGS
Disconnect primary power at the source before dis-
assembling the torch or torch leads.
Frequently review the Important Safety Precau-
tions (page 1). Be sure the operator is equipped with
proper gloves, clothing, eye and ear protection.
Make sure no part of the operator’s body comes into
contact with the workpiece while the torch is acti-
vated.
Sparks from the cutting process can cause damage
to coated, painted, and other surfaces such as glass,
plastic and metal.
Handle torch leads with care and protect them from
damage.
5.02 General Torch Maintenance
A. Cleaning Torch
Even if precautions are taken to use only clean air
with a torch, eventually the inside of the torch be-
comes coated with residue. This buildup can affect
the pilot arc initiation and the overall cut quality of
the torch.
WARNINGS
Disconnect primary power to the system before
disassembling the torch or torch leads.
DO NOT touch any internal torch parts while the
AC indicator light on the front panel of the power
supply is ON.
The inside of the torch should be cleaned with elec-
trical contact cleaner using a cotton swab or soft wet
rag. In severe cases, the torch can be removed from
the leads (refer to Section 5.07, Servicing Machine
Torch Components, or Section 5.06, Servicing Hand
Torch Components) and cleaned more thoroughly by
pouring electrical contact cleaner into the torch and
blowing it through with compressed air.
CAUTION
Dry the torch thoroughly before reinstalling.
B. Checking Center Insulator
The center insulator separates the negative and posi-
tive sections of the torch. If the center insulator does
not provide adequate resistance, current which is in-
tended for the pilot arc may be dissipated into the
torch head, resulting in torch failure.
WARNINGS
Disconnect primary power to the system before
disassembling the torch or torch leads.
DO NOT touch any internal torch parts while the
AC indicator light on the front panel of the power
supply is ON.
1. Remove the shield cup, tip, gas distributor, and
electrode from the torch. Disconnect the torch
leads from the power supply to isolate the torch
from power supply circuits.
2. Using an ohmmeter (set to 10K or higher), check
for continuity between the positive and negative
torch fittings. Infinite resistance (no continuity)
should be found. If continuity is found, refer to
Section 5.08, Torch and Leads Troubleshooting.
C. Torch O-ring Lubrication
The internal o-rings on the torch head assem-
bly (electrode, gas distributor and tip) require
lubrication on a scheduled basis. This will al-
low the o-rings to remain pliable and provide a
proper seal. The o-rings will dry out, becom-
ing hard and cracked, if the o-ring lubricant is
not used on a regular basis. This can lead to
potential leaks internally and externally. Fail-
ure of o-rings that seal against outside “air” en-
tering the torch assembly can cause severe con-
tamination. These contaminants can destroy or
shorten the parts life of tips, electrodes, and in-
ternal torch parts.